Protien

Question 1

What is a proteins primary structure?

Answer 1

This is a sequence of amino acids in the polypeptide chain.

Question 2

What is a proteins secondary structure ?

Answer 2

The polypeptide chain doesn’t remain flat and straight, hydrogen bonds form between the amino acids in the chain. This makes it automatically coil into an alpha helix or fold into a beta pleated sheet.

Question 3

What is a proteins tertiary structure?

Answer 3

The coiled or folded chain of amino acids is often coiled and folded further. More bonds form between different parts of the polypeptide chain, including hydrogen bonds and ionic bonds and disulphide bridges also form whenever two molecules of the amino acid cysteine come close together the sulphur in one cysteine bonds to the other sulphur atom in the other. For proteins form a single chain, tertiary structure forms their 3d structure.

Question 4

What is the quaternary structure of a protein?

Answer 4

Some proteins are made of several different polypeptide chains held together by bonds. The quaternary structure is the way these polypeptide chains are assembled together. For proteins made from more than one polypeptide chain (e.g. haemoglobin, insulin, collagen) the quaternary structure is the proteins final 3D structure.

Question 5

What are the monomers of proteins?

Answer 5

Amino acids

Question 6

What is a polypeptide?

Answer 6

A chain of more than two amino acids joined together.

Question 7

What sort of reaction links amino acids together?

Answer 7

Condensation reaction

Question 8

What is the name of the bond that comes between amino acids?

Answer 8

Peptide bond

Question 9

Name three bonds that may be formed between the amino acids in a polypeptide chain to form the tertiary structure of a protein.

Answer 9

Hydrogen bonds, ionic bonds and disulphide bridges.

Question 10

Explain how the shape of structural proteins make them specialised for their function.

Answer 10

Structural proteins are made of long polypeptide chains lying parallel to each other with cross links between them. This makes them physically strong.

Question 11

The biuret test is used to test for proteins.
a) what is added to the test solution to make it alkaline?
b)what is added next to the solution?
c) what would a positive test result look like

Answer 11

a) sodium hydroxide solution
b) copper(II) sulphate solution
c) it would be lilac